Method and apparatus for stretch wrapping a load

ABSTRACT

A leading end of packaging material is grasped in a packaging material holder while a load is wrapped. Packaging material is dispensed from a packaging material dispenser, and relative rotation is provided between the dispenser and a load to wrap packaging material around the load. The packaging material holder may be positioned on the rotating surface of a turntable but isolated from any electrical or fluid power source of a rotatable surface of the turntable. During the wrapping cycle, the packaging material holder moves downstream along the turntable, automatically releasing the leading end of the packaging material and automatically grasping a trailing end of the packaging material. The packaging material is weakened and then severed between the packaging material holder and the load. The packaging material holder is mounted to permit it to move upstream due to force exerted by the packaging material held in the holder.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a method and apparatus forwrapping a load with packaging material.

[0002] Loads have been stretch wrapped with stretch wrap packagingmaterial by securing a leading end of the packaging material to the loador a turntable clamp, dispensing the packaging material by providingrelative rotation between the load and a packaging material dispenser tocause the load to be enveloped by the packaging material, and severingthe packaging material between the load and a packaging materialdispenser. The relative rotation between the load and the dispenser canbe provided either by rotating the load on a turntable, or by rotatingthe dispenser around a stationary load. Stretch wrapping usually employsa web of stretch film as the packaging material, and the machinery canbe either automatic or semi-automatic.

[0003] Semi-automatic stretch wrapping machinery requires the operatorto attach a leading end of the packaging material to the load for eachload to be wrapped. This is typically accomplished by forming a rope inthe leading end of the film and then inserting this end between thelayers of the load or by tying the end of the packaging material to theedge of the supporting wood pallet or any suitable outcropping on theload. This attachment must be relatively strong since it provides thereaction to force needed to pull the film from the film dispenser duringthe initiation of the relative rotation between the load and the filmdispenser. The attachment or tying of the film makes film removal moredifficult after the load has been shipped to its destination.

[0004] Automatic stretch wrapping machines are significantly moreexpensive than semi-automatic machines. The automatic machines typicallyuse film clamps that grip the film web between two opposed surfaces, useelectrical or pneumatic actuators to open and close the clamps,typically supply electrical or pneumatic power to the actuators on aturntable through the journal of the turntable, and use hot wires orother expensive cutting devices are used to cut the film. Such filmclamps create a “tenting” effect during wrapping due to the distancebetween the clamp and the load during wrapping, resulting in wasted filmand loosely wrapped loads.

[0005] In light of the cost of such automatic machines, there is a needfor a method and apparatus for wrapping a load with packaging materialthat operates as effectively as those previously developed to allowautomatic release and clamping of portions of the packaging material butwhich can be manufactured at a lower cost.

SUMMARY OF THE INVENTION

[0006] Accordingly, the present invention is directed to a method andapparatus for wrapping a load with packaging material which providesadvantages over and obviates several problems associated with earliermethods and apparatus for wrapping a load.

[0007] To achieve these and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described, theinvention concerns an apparatus for wrapping a load with packagingmaterial, including a dispenser for dispensing packaging material, arotatable turntable for providing relative rotation between thedispenser and the load to wrap packaging material around the load, and apackaging material holder mounted on the turntable and isolated from anyelectrical or fluid power source by the rotatable turntable forautomatically grasping and releasing portions of the packaging material.

[0008] According to another aspect of the present invention, theinvention concerns an apparatus for wrapping a load with packagingmaterial, including a dispenser for dispensing packaging material, meansfor providing relative rotation between the dispenser and the load towrap packaging material around the load, and a packaging material holderfor holding and releasing the packaging material, the packaging materialholder being mounted to move upstream with the packaging material inresponse to force exerted on the packaging material by the packagingmaterial holder to permit the packaging material to sever at a weakenedportion between the packaging material holder and the load.

[0009] According to a further aspect of the present invention, there isprovided a method of wrapping a load with packaging material, includinggrasping a leading end of packaging material with a packaging materialholder mounted on a rotatable turntable and isolated from any electricalor fluid power source by the rotatable turntable, dispensing packagingmaterial from a packaging material dispenser and rotating the turntableto wrap packaging material around the sides of the load, automaticallyreleasing the leading end of the packaging material from the packagingmaterial holder, and automatically grasping a trailing end of thepackaging material with the packaging material holder at a pointupstream of the leading end.

[0010] According to another aspect of the present invention, a method ofwrapping a load with packaging material is provided including dispensingpackaging material from a packaging material dispenser and providingrelative rotation between the dispenser and the load to wrap packagingmaterial around the sides of the load, holding a portion of thepackaging material in a packaging material holder, weakening thepackaging material between the load and the packaging materialdispenser, and severing the packaging material at the weakened portionby tensioning the packaging material between the packaging materialdispenser and the load while permitting the packaging material holder tomove upstream with the packaging material toward the dispenser.

[0011] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned by practice of the invention.The objects and other advantages of the invention will be realized andattained by the method and apparatus particularly pointed out in thewritten description and claims as well as the appended drawings.

[0012] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory and are intended to provide further explanation of theinvention as claimed. The accompanying drawings are included to providea further understanding of the invention and are incorporated in andconstitute a part of the specification, illustrate an embodiment of theinvention, and together with the description serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1A is a perspective view of the load wrapping apparatus ofthe present invention;

[0014]FIG. 1B is a top view of the load wrapping apparatus of FIG. 1A;

[0015]FIG. 2 is an enlarged fragmentary perspective view of apparatusshown in FIG. 1;

[0016]FIG. 3A is a perspective view of the packaging material holder ofthe present invention;

[0017]FIG. 3B is a perspective view of the packaging material holder ofFIG. 3A mounted on a turntable;

[0018]FIG. 4A is a perspective view showing the packaging materialholder of FIG. 3 from an opposite side;

[0019]FIG. 4B is a perspective view of the packaging material holder ofFIG. 4A mounted on a turntable; and

[0020] FIGS. 5-11 are schematics showing movement of the packagingmaterial holder during the wrapping process of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The following text and accompanying drawings illustrate examplesof the present preferred embodiments of the present invention.

[0022] According to the invention, an apparatus is provided for wrappinga load with packaging material. As embodied herein and shown in FIGS. 1and 2, an apparatus for wrapping a load with packaging material isgenerally designated by the reference numeral 100 and includes apackaging material dispenser, means for providing relative rotationbetween a load and the dispenser, and a packaging material holder.

[0023] As shown in FIG. 1, a dispenser 102 is provided for dispensingpackaging material. Packaging material dispenser 102 dispenses a sheetof packaging material 116 in a web form. Packaging material dispenser102 includes a roll carriage 109 that supports a roll of packagingmaterial 108. Roll carriage 109 of dispenser 102 is mounted on andvertically moveable on a mast 104, shown in FIG. 1, to dispensepackaging material 116 spirally about load 124 as rotation is providedbetween load 124 and dispenser 102. Roll carriage 109, as embodiedherein and shown in FIG. 1, includes a support for packaging materialroll 108 and means for moving on mast 104. Alternatively, roll carriage109 may include a container for holding packaging material roll 108, anda slit for dispensing packaging material 116 from packaging materialroll 108.

[0024] In a preferred embodiment, stretch wrap packaging material isused. In the stretch wrapping art, stretch wrap packaging material isknown to have a high yield coefficient to allow the material a largeamount of stretch during wrapping. Various other packaging materials,generally not considered to be stretch wrap materials, such as netting,strapping, banding, and tape, can be used as well. Dispenser 102 mayalso include a variety of rollers, optionally including prestretchrollers for stretching the packaging material longitudinally and/ortransversely, to position, dispense, and stretch the packaging materialas packaging material 116 is being dispensed from the roll of packagingmaterial.

[0025] As shown in FIGS. 1 and 2, apparatus 100 includes means forproviding relative rotation between the dispenser and the load to wrappackaging material around the load. As embodied herein, the means forproviding relative rotation include a conventional turntable assembly120. Turntable assembly 120 has a rotatable turntable 122. Turntableassembly 120 may be positioned proximate a conveyor to receive a load124 to be wrapped from a load building area. Load 124 is rotated byrotatable turntable 122 of turntable assembly 120 to provide relativemotion between dispenser 102 and load 124.

[0026] Although not shown here, turntable assembly 120 may include anupper conveying surface with a plurality of powered rollers. As analternative to the turntable embodiment, relative rotation may beaccomplished by rotating dispenser 102 around a stationary load.

[0027] According to the present invention, a packaging material holderfor automatically releasing and grasping portions of the packagingmaterial is provided. As embodied herein and shown in FIGS. 1-4, thepackaging material holder includes packaging material holder 110,mounted on rotatable turntable 122 of turntable assembly 120. Packagingmaterial holder 110 includes a clamp for grasping, holding, andreleasing packaging material 116, and a mechanical movement foractuating the clamp. A roper for forming a rope of the packagingmaterial, and a packaging material weakener for weakening the packagingmaterial prior to severing are provided as well in this embodiment.

[0028] The clamp for holding and releasing packaging material 116, asshown in FIGS. 1-4, preferably includes opposed surfaces for graspingthe packaging material 116, such as jaws 112, 114. Jaws 112, 114 may bemade of any suitable material such as metal or plastic, and in anysuitable shape which will allow the jaws to grasp and hold the packagingmaterial without severing it. Jaws 112, 114 are preferably mounted on arail mounted on the turntable to allow jaws 112, 114 to translaterelative to Other alternative embodiments of the packaging materialholder may include other arrangements such as a single unopposedpackaging material engaging surface, such as a sticky or tacky surfacefor holding the packaging material, or in some instances, a vacuumsurface.

[0029] As shown in FIGS. 3 and 4, the mechanical movement is mounted onthe rotatable turntable and includes a floating cam in the form of aramp 150 attached to rotatable turntable 122 for supporting thepackaging material holder 110 on the turntable assembly 120. The uppersurface of ramp 150 forms a downstream pathway 152 at a first height,and the lower surface of ramp 150 from an upstream pathway 154 at asecond, lower height. “Upstream” and “downstream,” as used herein, areintended to define the direction of movement relative to the flow ofpackaging material from the dispenser 102. Thus, since the packagingmaterial flows from the dispenser, movement toward the dispenser andagainst the flow of packaging material from the dispenser is defined as“upstream” and movement away from the dispenser and with the flow ofpackaging material from the dispenser is defined as “downstream.” Asused herein, the leading end 30 of packaging material 116 is downstreamof the trailing end 32 of packaging material 116.

[0030] As embodied herein, the mechanical movement also includes a camfollower 158, which allows jaws 112, 114 to travel on the paths 152, 154of ramp 150. As shown in FIG. 5, the cam follower 158 sits at anupstream end of ramp 150 when holding the packaging material duringwrapping. Upon actuation of packaging material holder 110, cam follower158 moves to the top of the upstream end of ramp 150 and then travelsalong downstream path 152. Movement of cam follower 158 up onto theupper surface of ramp 150 automatically causes jaws 112, 114 ofpackaging material holder 110 to open. Jaws 112, 114 remain open as longas cam follower 158 is moving along the downstream path 152 of ramp 150.Once cam follower 158 reaches the end of downstream path 152 of ramp150, cam follower 158 rolls off of the end of ramp 150. Cam follower 158rolling off the end of ramp 150 automatically causes jaws 112, 114 toclose. As used herein, the term “automatically” is intended to mean thatmanual assistance is normally not required.

[0031] As embodied herein, the mechanical movement includes a cogmechanism 132 that rotates with packaging material holder 110 asturntable 122 rotates. Cog mechanism 132 consists of an engaging element134 and a chain element 136. Chain element 136 forms a complete loop,connected at each of its ends to engaging element 134. Chain element 136engages gears placed along the length of packaging material holder 110,and is moveable along the length of packaging material holder 110.

[0032] As embodied herein, an actuator for the mechanical movement isprovided. Preferably, the actuator is positioned apart from rotatableturntable 122 and the mechanical movement, so that the actuator does notrotate with rotatable turntable 122. As shown, the actuator includes apin 130. Engaging element 134 engages and is driven by pin 130 attachedto the non-rotating portion of turntable assembly 120. Pin 130 ismoveable between a non-upright position and an upright position, and pin130 is may be actuated to move to the upright position by a controller.In the upright position, pin 130 engages engaging element 134 of cog 132as cog 132 rotates with rotatable turntable 122, driving cog 132 in adirection opposite to that of the rotation. As cog 132 is driven alongthe length of ramp 150 of packaging material holder 110, jaws 112, 114of packaging material holder 110 moves along the length of ramp 150 inthe opposite direction, driven along the downstream path 152.

[0033] Cog element 132 also includes a release element 138 attached torotatable surface 122 of turntable 120. Release element 138 ispositioned at the upstream end of packaging material holder 110. Releaseelement 138 is positioned to knock down or disengage pin 130 from cog132 once cog 132 has moved from the downstream end of packaging materialholder 110 to the upstream end of packaging material holder 110. As thelength of packaging material holder 110 defines the full range ofmovement for cog 132, it is necessary to have a release once cog 132 hasreached the end of its range of motion. Release element 138 serves thispurpose.

[0034] Jaws 112, 114 of packaging material holder 110 moves alongupstream path 154 after it has reached the end of downstream path 152.Cam follower 158 is pulled along upstream path 154 by the force exertedupon packaging material 116 held in jaws 112, 114 by the roll ofpackaging material in dispenser 102. As shown in FIGS. 3 and 4,downstream path 152 is positioned above upstream path 154, such thatpackaging material holder 110 travels at a first level downstream, andat a second, lower level upstream.

[0035] As discussed above, packaging material holder 110 is mounted onthe top surface of rotatable turntable 122, and jaws 112, 114 ofpackaging material holder 110 are actuated to automatically open andclose at predetermined points along the length of ramp 150 of packagingmaterial holder 110. As embodied herein, packaging material holder 110is isolated from any electrical or fluid source of power by theturntable, in contrast to conventional devices in which the packagingmaterial holder is connected to an electrical or fluid source of powerby the turntable such as by a power connection through the journal ofthe turntable to the packaging material holder. This means that thepackaging material holder also does not receive any electrical or fluidpower from brushes, or the like, around a circumference of theturntable. The rotatable turntable 122 therefore does not carryelectrical or fluid power sources with it during rotation and acts as abarrier between the packaging material holder and any electrical orfluid source of power.

[0036] This enables the present invention to take advantage of thechanging of the angle of the packaging material relative to the load asthe turntable rotates. The rotation of the turntable is harnessed tolinearly move the packaging material holder along the turntable surface.During the last rotation of the turntable, as the angle becomes smallerand the packaging material approaches the side of the load, thepackaging material holder is driven by the rotation of the turntableinto a position to engage the trailing end of the packaging material.

[0037] In a preferred embodiment, as shown in FIG. 2, the movement ofthe turntable is utilized to move jaws 112, 114, opening and closingjaws 112, 114 to automatically release and grasp, respectively,packaging material 116. As discussed above, cog element 132 cooperateswith pin 130 to move jaws 112, 114 relative to rotatable turntable 122and thereby open and close jaws 112, 114. Pin 130 can be actuated tomove from the non-upright position to the upright position at apredetermined point in the wrapping cycle by the controller. Preferably,pin 130 is actuated during the last rotation in the wrapping cycle, andmost preferably during the last quarter turn of the wrapping cycle, toengage cog 132. Because cog 132 moves with rotatable surface 122 ofturntable 120, the rotation of the turntable can be used to move cog132. Cog 132 is moveably connected to jaws 112, 114 such that, if cog132 moves to the left, jaws 112, 114 will move to the right.Alternatively, if cog 132 is moved to the right, jaws 112, 114 will moveto the left. Thus, it is the rotation of the turntable, rather than anelectrical or fluid power source carried by the rotating turntable, thatis used to move and thereby automatically open and close jaws 112, 114.

[0038] Other mechanical movements including various combinations ofmechanical or electrical devices may be used to cause movement andopening and closing of jaws 112, 114. Alternatively, turntable 122 maynot rotate while the packaging material is automatically released andgrasped by the packaging material holder. In such a situation, packagingmaterial holder 110 could be powered by a separate power source such asa motor placed on the floor or near the turntable.

[0039] According to one aspect of the invention, a roper may be providedfor forming a rope of packaging material. As discussed herein, “roping”packaging material means rolling or twisting or collapsing a portion ofthe web of packaging material 116 to shape it into a rope-like form. Inorder to withstand a starting force during wrapping, at least 20% of theweb of packaging material 116 should be held by the packaging materialholder. For example, a web of packaging material twenty (20) inches highmay have a five (5) or six (6) inch portion formed into a rope. Thisallows the jaws 112, 114 to engage a rope 118 and a portion of the webof packaging material 116, rather than holding only a small portion ofthe packaging material 116 between the opposing surfaces. As seen inFIGS. 1 and 2, jaws 112, 114 can grasp a substantial cross section ofthe web of packaging material 116 when it has been roped. This gives thelower portion of the web of packaging material 116 between jaws 112, 114and dispenser 102 the triangular shape seen in FIGS. 1 and 2. Asembodied herein and shown in FIG. 4, the roper includes scooping element140, which is attached to and moveable with jaws 112, 114 of packagingmaterial holder 110. As jaws 112, 114 and scooping element 140 movealong downstream path 152, they move from a flat position to an uprightposition. As scooping element 140 changes position, it captures the webof packaging material 116 and rolls the packaging material 116 into arope 118 as it moves into the full upright position.

[0040] Although the present invention, as embodied herein, uses a scoopfor roping, it is possible to use a wheel to roll the lower edge of thepackaging material upward to form a rope of packaging material or to usea combination of a scoop and a wheel. Alternatively, other means such asa ramp may be used to gather the packaging material together to form arope.

[0041] A positioner may be provided for passing the packaging materialover the packaging material holder during wrapping. As embodied hereinand shown in FIGS. 3 and 4, the positioner for passing the packagingmaterial over packaging material holder includes wheel 141. Wheel 141rolls a lower edge of packaging material 116 as it passes over wheel141, lifting it above packaging material holder 110. Thus it causespackaging material 116 to pass above packaging material holder 110,avoiding the tenting effect of holders in the prior art.

[0042] As embodied herein and shown in FIG. 3, a packaging materialweakener is provided for weakening the packaging material 116 betweenthe load 124 and the dispenser 102. The packaging material holder 110preferably includes a cutter 142. Cutter 142 may include an opposedcutting element, such as scissors, or a single cutting element such as arazor blade. Cutter 142 is connected to an actuation lever 144 whichmoves with jaws 112, 114. Actuation lever 144 is moveable between a freeposition and a contact position. As jaws 112, 114 move along downstreampath 152, jaws 112, 114 open, automatically releasing packaging material116, scooping element 140 moves upward to scoop the lower edge of theweb of packaging material 116 into a rope 118, and actuator lever 144moves from the free position to the contact position. When actuationlever 144 is in the contact position, cutter 142 is activated to weakenpackaging material 116 by cutting at least a portion of the web ofpackaging material 116, including the rope 118 of packaging material116.

[0043] According to one aspect of the present invention, the apparatusmay include means for securing a trailing end of packaging material tothe load. As embodied herein, the means for securing includes a filmwipedown mechanism for wiping a film tail onto the load after thepackaging material has been cut. As shown in FIG. 1, the film wipedownmechanism 180 includes wipe loops 182 and a wipe arm 184. This allows afilm tail to be wiped onto load 124 as the packaging material 116 iscut.

[0044] Other cutters and wipedown arrangements may also be used.

[0045] A method for wrapping a load according to the present inventionis shown in FIGS. 5-11. As shown in FIG. 5 and according to a preferredembodiment of the present invention, a load 124 is conveyed by aconveyor 118 to a turntable assembly 120 in the wrapping station andload 124 is positioned on top of rotatable turntable 122 of turntableassembly 120. Jaws 112, 114 of packaging material holder 110 hold aleading end portion 30 of a roped sheet of packaging material 116,preferably stretch wrap packaging material. Cog 132 is positioned at adownstream end of packaging material holder 110, and jaws 112, 114 arepositioned at the upstream end of packaging material holder 110, and camfollower 158 is positioned to the upstream side of ramp 150 (FIG. 5).

[0046] Rotatable turntable 122 begins to rotate and packaging material116 is dispensed from dispenser 102 about load 124. As packagingmaterial 116 passes over packaging material holder 110, wheel 41 engagesthe lower edge of the packaging material, ensuring that the packagingmaterial passes over packaging material holder 110 and does not becomecaught on it. This avoids a “tenting” effect and allows tight wrappingof the load. Load 124 is spirally wrapped with packaging material 116 asdispenser 102 moves vertically along mast 104 as the relative rotationis provided.

[0047] As the load is wrapped and rotatable turntable 122 enters thelast rotation of the wrapping cycle, see FIG. 6, a pin 130 attached to anon-rotating portion of turntable assembly 120 is actuated by thecontroller, moving from a non-upright position to an upright position.As the turntable 122 rotates, pin 130 engages engaging element 134 ofcog 132, located on top of rotatable turntable 122 of turntable assembly120. Pin 130 causes cog 132 to move upstream (in a direction opposite tothat of the rotation) along the top surface of rotatable turntable 122of turntable assembly 120 as rotation continues.

[0048] As cog 132 moves, the movement causes cam follower 158 to move uponto the top of ramp 150, to the start of downstream path 152. When camfollower 158 moves to the top of ramp 150, jaws 112, 114 open,automatically releasing leading end portion 30 of packaging material 116(see FIG. 7). Additionally, dispenser 102 is shut off to tension thefilm between load 124 and dispenser 102.

[0049] As cog 132 moves, it drives jaws 112, 114 downstream along adownstream path 152 of ramp 150. Concurrently, scooping element 140begins to move from a retracted position to an upright position,scooping a trailing end 32 of packaging material 116 into a rope 118. Asjaws 112, 114 continue to move downstream, they remain open, receivingtrailing end 32 of packaging material 116 formed into rope 118 asscooping element 140 reaches its full upright position (see FIG. 8). Ascog 132 reaches the upstream end of packaging material holder 110, camfollower 158 reaches the end of path 152 and rolls off the end of ramp150, causing jaws 112, 114 to automatically clamp shut on and grasptrailing end 32 of roped packaging material 116.

[0050] As scooping element 140 is moving from the retracted position tothe full upright position (see FIG. 9), actuation lever 144 moves fromthe free position to the contact position, activating cutter 142 toweaken packaging material 116 between jaws 112, 114 and load 124 afterjaws 112, 114 have automatically grasped the trailing end 32 ofpackaging material 116. At the same time, pin 130 encounters releaseelement 138 at the upstream end of packaging material holder 110, whichknocks pin 130 into its non-upright position, causing it to disengagefrom cog 132.

[0051] Once jaws 112, 114 have reached the downstream end of packagingmaterial holder 110, they grasp and hold trailing end 32 of packagingmaterial 116. Packaging material 116 extends between dispenser 102, jaws112, 114, and load 124. The tension in packaging material 116 betweendispenser 102 and jaws 112, 114 causes jaws 112, 114 to move upstreamtoward the dispenser (see FIG. 10). Jaws 112, 114 move upstream as camfollower 158 travels along upstream path 154 of ramp 150 in response tothe force exerted by the packaging material. Because cam follower 158can travel underneath the floating cam (ramp 150) as it returnsupstream, instead of traveling on top of ramp 150, jaws 112, 114 remainshut as they travel upstream. As jaws 112, 114 holding trailing end 32of packaging material 116 move upstream, packaging material 116 istensioned between jaws 112, 114 and load 124. Because of the relativemovement of the packaging material holder, packaging material 116 thenbreaks at the weakened portion between load 124 and jaws 112, 114,rather than between the packaging material holder and the dispenser.This provides a true automatic operation by maintaining the packagingmaterial to be held in the packaging material holder before, during andafter severing.

[0052] Other arrangements for permitting the packaging material holderto move upstream with the packaging material toward the dispenser mayalso be provided.

[0053] Although the arrangement illustrated in the drawings weakens andthen breaks the packaging material between the load and the jaws, it isin the scope of the one aspect of the invention to weaken the filmsomewhere between the dispenser and the load, and then break the filmbetween the jaws and the load. Additionally, it is possible to simplysever the packaging material, as opposed to weakening and then breakingthe packaging material.

[0054] All of the functions can be controlled with a conventionalmicroprocessor, electromechanical controller, or other controllerdevices which are conventionally used with the stretch wrappingapparatus.

[0055] The present invention as embodied herein and described above,allows fully automated wrapping of loads at a drastically reduced costand in an extremely efficient manner. The simplicity of the apparatusand its function allows existing rotary stretch wrapping apparatus to beretrofit to become fully automated. By using the rotation of theturntable to facilitate the releasing, grasping, and cutting of thepackaging material, the need to supply power through the rotatableturntable of the turntable assembly to the packaging material holder andthe need for expensive timing circuits is eliminated.

[0056] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover all modifications andvariations of this invention that come within the scope of the appendedclaims and their equivalents.

What is claimed is:
 1. A method of wrapping a load with packagingmaterial, comprising: grasping a leading end of packaging material witha packaging material holder mounted on a rotatable turntable andisolated from any electrical or fluid power source of by the rotatableturntable; dispensing packaging material from a packaging materialdispenser and rotating the turntable to wrap packaging material aroundthe sides of the load; automatically releasing the leading end of thepackaging material from the packaging material holder; and automaticallygrasping a trailing end of the packaging material with the packagingmaterial holder at a point upstream of the leading end.
 2. The method ofclaim 1, wherein the automatically grasping includes grasping thepackaging material with jaws and the automatically releasing includesreleasing the packaging material from the jaws.
 3. The method of claim 1including engaging and actuating the packaging material holder with anactuator stationed apart from the rotatable turntable.
 4. The method ofclaim 1 including an actuator stationed apart from the rotatableturntable, and wherein the packaging material holder includes amechanical movement engageable by the actuator to actuate the packagingmaterial holder.
 5. The method of claim 1, wherein the automaticallyreleasing includes using movement of the turntable to release thepackaging material from the packaging material holder.
 6. The method ofclaim 1, wherein the packaging material holder includes jaws and theautomatically releasing includes translating the jaws relative to theturntable to open the jaws to release the packaging material.
 7. Themethod of claim 1, wherein the packaging material holder includes jawsand the automatically grasping includes translating the jaws relative tothe turntable to close the jaws to grasp the packaging material.
 8. Themethod of claim 1 including automatically severing the packagingmaterial.
 9. The method of claim 1, including automatically severing thepackaging material and weakening the packaging material prior tosevering it.
 10. The method of claim 1, including automaticallyweakening the packaging material prior to severing the packagingmaterial.
 11. The method of claim 1, including automatically weakeningthe packaging material with an opposed blade.
 12. The method of claim 1,including roping the packaging material prior to automatically graspingthe packaging material.
 13. The method of claim 1, including severingthe packaging material and roping the packaging material prior tosevering the roped packaging material.
 14. The method of claim 1,including securing the trailing edge of the packaging material to theload after severing the packaging material.
 15. The method of claim 1including roping, weakening, and severing the packaging material.
 16. Amethod of automatically wrapping a load with packaging material,comprising: automatically dispensing packaging material from a packagingmaterial dispenser and providing relative rotation between the dispenserand the load to wrap packaging material around the sides of the load;automatically holding a portion of the packaging material in a packagingmaterial holder; automatically weakening the packaging material betweenthe load and the packaging material dispenser; and automaticallysevering the packaging material at the weakened portion by tensioningthe packaging material between the packaging material dispenser and theload while permitting the packaging material holder to move upstreamwith the packaging material toward the dispenser.
 17. The method ofclaim 16, wherein providing relative rotation includes rotating aturntable having the packaging material holder mounted on it.
 18. Themethod of claim 16, wherein the packaging material holder is mounted ona turntable and is mechanically repositioned downstream prior to the Aweakening due to the rotation of the turntable.
 19. The method of claim16, wherein the packaging material holder is mounted on a turntable andjaws of the packaging material holder are automatically opened andclosed by a power source isolated by the rotatable turntable.
 20. Themethod of claim 16, wherein the packaging material is roped into thepackaging material holder prior to weakening.
 21. The method of claim16, including roping the packaging material into the packaging materialholder and weakening the packaging material by cutting a portion of theroped packaging material.
 22. The method of claim 16, wherein theautomatically weakening includes cutting a portion of the wrappedpackaging material with an opposed cutting element.
 23. The method ofclaim 16, including moving the packaging material holder downstreamprior to weakening the packaging material.
 24. The method of claim 16,including moving the packaging material holder downstream prior toweakening the packaging material, and moving the packaging materialholder upstream subsequent to weakening the packaging material.
 25. Themethod of claim 16, including weakening the packaging material betweenthe packaging material holder and the dispenser, and severing thepackaging material between the packaging material holder and the load.26. The method of claim 16, wherein the weakening and severing occurbetween the load and the packaging material holder.
 27. The method ofclaim 16, wherein the weakening is prior to the holding.
 28. The methodof claim 16, wherein the holding is prior to the weakening.
 29. Themethod of claim 16, including automatically releasing the leading end ofthe packaging material from the packaging material holder prior toweakening.
 30. The method of claim 16, wherein the packaging materialholder moves downstream to automatically release and grasp the packagingmaterial, and the packaging material holder moves upstream to sever thepackaging material.
 31. The method of claim 16, wherein the packagingmaterial holder is mounted on a cam follower and rides downstream on aramp formed by a top portion of a cam at a first height to automaticallyrelease and grasp the packaging material, and the packaging materialholder rides upstream along a lower portion of the cam at a lower heightto provide tension on the weakened portion of the packaging material tosever the packaging material between the load and the packaging materialholder.
 32. An apparatus for wrapping a load with packaging material,comprising: a dispenser for dispensing packaging material; a rotatableturntable for providing relative rotation between the dispenser and theload to wrap packaging material around the load; and a packagingmaterial holder mounted on the rotatable turntable and isolated from anyelectrical or fluid power source by the rotatable turntable forautomatically grasping and releasing portions of the packaging material.33. The apparatus of claim 32 including an actuator, stationed apartfrom the rotatable turntable, for engaging and actuating the packagingmaterial holder.
 34. The apparatus of claim 32 including an actuatorstationed apart from the rotatable turntable, and wherein the packagingmaterial holder includes a mechanical movement engagable by the actuatorto actuate the packaging material holder.
 35. The apparatus of claim 32,wherein the packaging material holder is mounted to translate along apath on the turntable, and including a mechanical movement for movingthe packaging material holder in a downstream direction on the path. 36.The apparatus of claim 32, wherein the packaging material holder ismounted to translate along a path on the turntable to permit thepackaging material to pull the packaging material holder in an upstreamdirection on the path.
 37. The apparatus of claim 32, wherein thepackaging material holder includes a floating cam mounted on theturntable to keep the packaging material holder open when movingdownstream and closed while moving upstream.
 38. The apparatus of claim32, including a floating cam mounted on a turntable for moving thepackaging material holder and a cam follower mounted to the packagingmaterial holder, wherein the cam includes a downstream ramp at a firstheight and an upstream ramp at a second lower height.
 39. The apparatusof claim 32, including a weakener for weakening the packaging material.40. The apparatus of claim 32, wherein the packaging material holderincludes jaws for holding the packaging material.
 41. The apparatus ofclaim 32, including means for forming a rope of packaging material anddirecting it into the open packaging material holder.
 42. The apparatusof claim 32, including means for securing a trailing end of packagingmaterial to the load.
 43. An apparatus for wrapping a load withpackaging material, comprising: a dispenser for dispensing packagingmaterial; means for providing relative rotation between the dispenserand the load to wrap packaging material around the load; and a packagingmaterial holder for automatically holding and releasing the packagingmaterial, the packaging material holder being mounted to move upstreamwith the packaging material in response to force exerted on thepackaging material by the packaging material holder to permit thepackaging material to sever at a weakened portion between the packagingmaterial holder and the load.
 44. The apparatus of claim 43, including apackaging material weakener.
 45. The apparatus of claim 43, wherein thepackaging material holder severs the weakened packaging material as thepackaging material holder moves upstream.
 46. The apparatus of claim 43,wherein the means for providing relative rotation is a turntable and thepackaging material holder is mounted on the turntable.
 47. The apparatusof claim 43, wherein the packaging material holder is mounted on arotatable turntable and the packaging material holder is isolated fromany source of electrical or fluid power by the rotatable turntable, 48.The apparatus of claim 43, including means for roping the packagingmaterial into the packaging material holder.
 49. The apparatus of claim43, wherein the packaging material holder is moveable downstream andincluding a packaging material weakener, wherein the packaging materialweakener is actuated as the packaging material holder is moveddownstream.
 50. The apparatus of claim 43, wherein the packagingmaterial holder includes jaws for grasping and holding the packagingmaterial.
 51. The apparatus of claim 43, including means for moving thepackaging material holder downstream to automatically release a leadingend of the packaging material from the packaging material holder. 52.The apparatus of claim 43, including means for moving the packagingmaterial holder downstream to automatically release a leading end of thepackaging material from the packaging material holder, wherein the meansfor moving is isolated from a power source causing the relativerotation.
 53. The apparatus of claim 43, including means for moving thepackaging material holder downstream to automatically grasp a trailingend of the packaging material from the packaging material holder. 54.The apparatus of claim 43, including means for moving the packagingmaterial holder downstream to automatically grasp a trailing end of thepackaging material from the packaging material holder, wherein the meansfor moving is isolated from a power source causing the relativerotation.
 55. The apparatus of claim 43, further including means formoving the packaging material holder downstream to automatically releasea leading end of the packaging material from the packaging materialholder and to automatically grasp a trailing end of the packagingmaterial from the packaging material holder.
 56. The apparatus of claim43, including a packaging material weakener, wherein the packagingmaterial weakener includes an opposed cutting element.
 57. The apparatusof claim 43, further including means for securing a trailing end ofpackaging material to the load.